Impact tool



E. H. SHAFF IMPACT TOOL June 21; 1927,

Filed oct. 1o,- 1922 2 Sheets-Sheet l mmh mw mm. Am mw. MW hw E n 52511521@ f,

June 21 1927.

E. H. SHAFF IMPACT Toor.

Filed oct. 1o. 1922 l 2 Sheets-Sheet 2*.

Patented June 21, 1927.

Uri-iran s'rarnsV PATENT oFFlcE.

ERNEST H. SHAFF, OF GRAND HAVEN, MICHIGAN, ASSIGNOR T WILLIAM H. KELLER,

IN C., OF GRAND HAVEN, MICHIGAN, A CORPORATION 0F MICHIGAN.

IMPACT TOOL.

' Application filed October 10, 1922. Serial No. 593,577.

My invention relates to impact tools, and particularly but not exclusively to manually supported impact tools of the hammer Jtype. l My invention, which has among itsv objects the' provision of simplicity inl construction and efliciency in operation, willy be best un# dci-stood from the following. description when read in the light of the accompanying drawing of one specic embodim-entof my invention selectedy for illustrative purposes, while the scope of my invention will be more particularly pointed out in the appended claims.

1n the drawing-:-

Fig. 1 shows a longitudinal sec-tion of an embodiment of my invention applied to a rivet breaker type of impact. tool;

Figs. 2 and glare longitudinal sections of theA rearward end of the machine corresponding to Fig. 1 with the: valve moved to dil'l'erent positions 51 f Fig. 4 is a section on the line' 4-4 of Fig, 1;

Fig. 5 is an end elevation of the machine;

Fig. G is af section on theline 6 6 of Fig. il; andi Fig. 7 is aI side elevation of the rearward end of the machine, parts shown inthe section on the line 7 7 of Fig. 5;

Figs. 8 and Scare sections onI the lines 8-8 and 9-9vof 7.

Referring to the drawing, which as heretofore indicated shows al specific embodinient of one type of my invention, 1 have provided a cylinder in the form of a tube 1 which is exteriorly screw threaded at opposite ends. 'The screw'threads at the forward end of the cylinder-'carry the sleeve 3 serving as a retainer for the working tool 5, while the screw threads` at the rearward end arry they headbloclrl the latter having a bore 9 which coincides with the bore 11 of the tube. 1n: the cylinder chamber provided by the bores 9 and 11 1l mountfor reciprocation the hammerpiston` 13, thelatter being arranged. to strike at the end: ofits forward stroke the rearward end oli the shank 14 of the working tool', which shank fits the bore ll. andj is retained' therein. by the sleeve 3.

For supporting the devicer the headblock is provided at its rearward` end with` a transversed: bore 15 which receives a hollow bar 17 the,vr projecting ends of which form the c' supporting hand-le for the machine.

. At one sideof the headblock is` an: enlargement 19A provided with a cylindrical bore 21 through which extends the `sleeve 23. The ends of the sleeve 23' are interiorly screw threadedf,., and receivel the screw threaded ends of plugs and 27. The plugs which thus serve to close the ends of the sleeve 23 are provided with hexagonal heads 29, cor,- ners 31 of which overlap the edges of the bore 21 and bear on the end surfaces of the headblock adjacentr said edges, and thereby serve to prevent movement of thel sleeve 23 in the bore 21'. n i

The interior of thesleeve 23 forms a valve chamber in which reciprocates af pistonI valve l for controlli-ng the `operation of` the hammer piston 13. This controlling valvecomprises a forward head133 and a rearward head 35, the heads being connected by the reduced:y diaineter portion 37 of the valve. The valve stem 39 proj ecting through asuitable orifice in the plug 25` serves as a convenient means for connecting the valve to-l the valve: con trolling member for actuating it.

yFor actuating the controlling valve-1. provide a controlling member herein exemplified by the handle lever 41, the latter having a bifurcated portion 48 which straddlesthe cylinder just forward of the headblock and is pivotally supported at an' intermediate positron on ears l projecting forwardly from the headblock.. The ears 45Icarry outwardly projecting trunnions 47 which` enter suitable pcrforations in the `handle lever and thus is formed the pivotall support. The end` por'- tions of the bifurcation of the handlel lever are connected' to the endi of the valve stem remote from the valve by means of apin 49 which entends through and projects' from the valve stem', and is received inv perforations in the ends'of the bifurcation; It will be noted that by pivotingthe handle lever as described saidf lever is substantially bal.- a'nced in its effect on the valve.

At the rearward end of the headblock is an ropening lv for receiving the connection for an air hose constituting a source of mo.- tive fluid supply.v Connecting the opening 5l with the interior of they valve chamberis a passage. Leading fromthe valve'cham.- ber at a point forwardly of theplace of communication of the passage 53 therewith is a second passage 55 which leads to the cylinder chamber at a point spaced from its extreme rearward end. A third passage 57 connects the interior of the valve chamber at a ypoint forward of the point of communication of the passage 55 therewith to the atn'iosp'here.

lVith this arrangement of parts it will be clear that with the valve in the position shown by F ig. 1 motive fluid will be cony ducted from the opening 51 to -the rearward end of the cylinder by way ofr the passage 53, the chamber formed by the reduced diameter portion 37 of the valve, and .the passage 55, 'the passage 57 at this time being closed by the head 33 of the valve; and, further, that with the parts in the rposition shown by Fig. 2, motive fluid will be conducted from the rearward end of the cylinder to the atmosphere by way of the passage 55, the chamber accorded by the reduced diameter portion 37 of the valve, and `the passage 57, the passage 53 in this position of parts being rlosed by the head 35 of the valve. In practicethe valve is moved to the position shown by Fig. 1 to permit motive fluid to drive the piston forwardly to strilre the tool, and is moved to the position shown by Fig. 2 to exhaust such motive fluid.

For returning the piston after the motive fluid which has driven the same forwardly is exhausted, I subject the rearward end of the piston chamber to suction. To this end I create a jet of motive fluid and cause the suction induced thereby to create a partial vacuuin in the rearward end of the cylinder. For giving effect to the partial vacuum I connect the forward end of the cylinder to any source of relatively low pressure compared to the pressure of the inotive iuid supply. In the presentembodiment of my invention this connection is exemplified by passages 59 which place the forward end of the cylinder in communication with the atmosphere.

In order to form the ejectors heretofore referred to I provide the opposite sides of the headblock with enlargements 61, each of which is provided with a longitudinal bore 63, the forward end of which is flared as at 65, while the rearward end is enlarged and screw threaded for receiving the plug 67. The plug 67 is provided at an intermediate portion with an annular groove G9, and with an axially located passage 71, the latter being of small bore and leading from the forward face of the plug rearwardly 'to a transverse passage 73 connected with the annular groove 69. The forward end of the plug is reduced to fit the small diameter Aportion of the bore 63, the latter being enlarged immediately adjacent the forward end of the plug to form a chamber 75. In

this manner the portion of the bore 63, 'forwardly of the annular groove 75, forms the combining tube -of an ejector, the annular groove 75 the combining chamber of an ejector', and the bore 71 of the plug the nozzle of an ejector.

For supplying the nozzler ofthe ejector with pressure fluid I provide a passagel 77 formed on the outer surface of the sleeve 23 and opening into 'the valve chamber by means of the radial passage 79 located just rearwardly the point of communication of the passage 53 of the valve chamber, while adjacent the rearward end of the passage. 7 7 the headblock is provided with a transvers passage 81 which intersects the passage 77 and opens into the annular grooves 69 in the plugs 67 of the ejectors. Further the valve head 35 is provided with a recess 83 which, when the valve is moved to the position shown by Fig. 3, establishes communication between the passage 79 and the' passage 53 so 'as to supply motive fluid tothe nozzles of the ejectors. j

For connecting the combining chambers 75 of the ejectors to the cylinder I provide the bore 21` of the headbloclr, which bore receives the sleeve 23 with a semilannular groove 85 communicating with the passage 55. Leading from the semi-annular groove 85 is a `longitudinal groove V87v formed in the surface of the bore 23, the rearward end of the groove being placed into coinmunication with the interior ofthe sleeve 23 by means of a slot 89. Leading from the interior of the sleeve in the plane of the slot 89 are transverse passages 91 which open into the combining chambers 75. In this manner it will be understood that with the parts in the position shown by Fig. 3 not only will motive fluid be supplied to the nozzles of the ejectors, but that in addition the rearward end of the cylinder will be connected to the combining chambers 75 by means of the passage 55, the semi-annie lar groove 85, groove 87, slot 89, the rearward end of the valve chamber, and pas? sages 91.

To summarize the operations hereinbefore explained, it is pointed out that with the valve in the position shownby Fig. 1 motive fluid Vis admitted to t-he interior of the cylinder to drive the piston forwardly, the exhaust from the cylinder at this'tinie being closed, and the ejectors being inoperative. After the blow is struck the valve is moved to the position shown by Fig. 2 which connects the' interior of the cylinder' with the atmosphere by way of the passages 55, the chamber about the reduced diameter portion 37 of the valve anc the passage 57 which exhausts the motivefluid which has acted to drive the piston forwardly. The valve is now moved to its position shown by Fig. 3 which interrupts the lconnect-ion `tion shown by Fig. l to that shown by Fig.

2. In the present form of mydevice for this purpose I form through the head 35 of the valve a passage 93 of small diameter'. VV'th this construction, when the valve is moved into vthe position shown by Fig. l, motive fluid passes through the passage 93 to the chamber at the rear of the valve, Which moves the valve to the. position shown by Fig. 2, so as to cut off the inlet. of air to This' the cylinder and open it to exhaust. of course also opens the Vspace at the rear of' the valve -toitlic atmosphere and exhausts `the air previously admitted to said space.

I have found thatbymalring the valve move or tend to .move automatically from the position shown' by Fig. l to the position shown by Fig. 2 that the recoil 'heretofore incident to this type of machine is-practically eliminated. This follows from the fact that it eliminates the tendency of the operator lnot to move 'the valve to return the piston until he is conscious of the blow. Specifically1 I have found that when the valve is moved into the position shown by Fig. l, the piston almost instantly strikes the tool and .if the valve is keptin this position long enough the cylinder fills up with air at high pressure and causes a violent recoil. lVith the present arrangement however the `valve will bemoved to exhaust the cylinder before the recoil can taire pla-ce; and further, 'when the valve reaches the position shown by Fig. 2 the tendency of the operator is to keep. the valve in that posi- .tion for sufficient time to enable the cylinder 'to fully eXl'iaust'before the valve is moved "to the position shown by Fig. 3, which results in theI piston being returned more quickly.

Although I have described for purposes of illustration one specific embodiment ot' one .type of my invention it is to be understood that I am not limited thereby to its particular mechanical details, but within the scope of my invention Wide deviations may be made therefrom without departing from vrthe spirit of my invention.

Claims: l

l. Anfimpact tool having, in combination, a cylinder, a hammer piston, a tool for actuation by said hammer piston, means forming an ejector, a source of pressure fluid supply, piston Vactuating imeans including a coordinated controlling valve mechanism 4and means forming ports and passages con- Vfluid from said source to vsaid ejector With connectionof the latter to said end of said i' cylinder, said valve mechanism also operative to effect by said ports and passages exhaust of said pressure fluid admitted -to said cylinder by passages independentof saidejector.

2. An impact tool having, in combination, a cylinder, ay hammer piston, a tool for actuation by said hammer piston, means `forming an ejector, a source of pressure fluid supply, piston actuating means including a coordinated controlling valve mechanism and means `forming ports and passages controlled yby said valve mechanism, said valve mechanism operative for effecting by said ports and passages alternate admission of pressure Vfluid from said source tovan end of said cylinder and admission of pressure fluid from said source to y.said ejector with connection of the latter to said end of sait cylinder, said valve mechanism havingA a Ypesi tion in which said ports and passages are inoperative to admit-pressure fiuid to said end of said cylinder and to said ejector, said ports and passages when said valve is in said position connecting said 'end of said cylinder vto the atmosphere.

An impactftoo'l liaving, in combination, a cylinder, ahammer piston,a tool rfor actuation by said ?hanimer' piston, means -foriiiing an ejector, a source yof pressure fluid.

supply, piston actuating y'means including a coordinated controlling "valve mechanism and means forming ports and passages conti'olled by said valve mechanism, said valve mechanism operative for effecting by said ports and passages alternate admission of pressure fluid from said source to an end of said cylinder and admission of pressure fluid fromi said sourceto said ejector with connection of the latter to said end-of said cylinder, said valve mechanism having a position in Vwhich said ports and pasfi'ages are inoperative to vadmit pressure fluid to said end of said cylinder and to Vsaid ejector, said ports and passages When said valve is in said position connecting said end of said cylinder lto the atmosphere independently of said ejector. j

, e. An impact tool having, in combination,

a cylinder, .a hammer piston, `a tool for acl tuation by said hammer piston, means forming an ejector, al source of pressure fluid supply, piston actuating means including a coordinated controlling valvemechanism and .means forming ports and passages controlled by said valve mechanism, said valve lmechavos iiism operative l'or effecting' by said ports and passages alternate adn'lission of pressure fluid from said source to an end o' said cylinder and admission of pressure fluid from said source to said ejector with connection oli the latter to said end of said cylinder, said valve mechanism also operative to enforce by said ports and passages exhaust of the pressure fluid admitted to said end ot' said cylinder before pressure fluidmay be admitted to said ejector.

5. An impact tool havine', in combination, a cylinder, hamnir piston, a tool for actuation by said hammer piston, means forming an ejector, a source of pressure fluid supply, piston actuating means including a coordinated controlling;- valve Vmecluinism and means forming ports and passages' controlled by said valve mechanism., said valve mechanism operat-ive for effecting by said ports and passages alternate admission ot pressure fluid from said source to an end of said cylinder and admission of pressure fluid from 'said source to said ejector with connection of the latter to said end ot said cylinder', said valve mechanism also operative to enforce 3y said ports and passages exhaust ot' the pressure fluid admitted to said end of cylinder before pressure fluid may be admitted to said ejector and by passages independent ott said ejector.

6. .en impact tool having, in combination, a cylinder, a hammer piston, a tool for actuation by said hammer piston, means forming an ejector, av source et pressure fluid supply, piston actuating; means including a coordinated controlling valve mechanism and means forming ports and passages controlled by said valve mechanism, said valve mechanism operative for effecting` by said ports and passages alternate admission of pressure fluid from said source to van end of said cylinder andl admission of pressure fluid from said source to said ejector With connection ot the latter to said end of said cylinder, said valve mechanism having operating` positions for `successively eii'ecting; by said. ports and passages the admission of pressure Vlluid to said cylinder, then the exhaust ot said pr `ure fiuid, and linally a lmission of presre uuid to said ejector and connection oi said ejector to the end of said cylinder.

if. A hand held impact tool having, in

combination, a cylinder, a hammer piston, ay

tool for actuation by said hammer piston, means ,forming an ejector, a source oi'f pressure fluid supply., piston and ejector act-uatim;` means includinga coordinated controlling valve mechanism and means forming; ports aud pal-'sages controlled by said valve mechanism, said valve inecl'ianism having two operating` positions operativo to eliect by said ports and passages alternate admission oit pressure fluid to an end ot said cylinder and operation of said ejector to elfect creation of a partial vacuum in said end of said cylinder, and a third operatingv position intermediate said two positions for connecting); said end of' said cylinder' to the atmosphere. Y v

8, A hand held impact tool having', in

combination, a cylinder, a hammer pist-on, lool for actuation by said hammer piston, means 'forming an ejector, a source of pressure fluid suppli, piston and ejector actuating means including,l a coordinated controlling valve mechanism and means torming; ports a d passages controlled bysaid valve iueclianism, said valve mechanism having' two 'operating positions operative to ell'oct by said port-s and passa-ges alternate admi-:sion of pressure fluid to an end of said cylinder and operation of. said ejector to i lct crea end of said cylinder, and a third operating` posit-ion intermediate said two positions for usine' said ports and passages to connect iid end of said cylinder to the atmosphere by passage-,f indexL endcnt ot said ejector.v

S). illu impact tool having, incombination, a cylinder, ay hammer piston, a ytool toractuation by said hammer piston, an ejector having means Vroi-ming` et orifice and a suction orifice, a source of pressure fluid supply; means forming passages for connecting f.

source to an end ot said @vlinder and toy sai d said said ant jet orifice, said-end of said cylinder to suction orifice and to the atmosphere, said suction orifice to the atmosphere;

.the last named means including a relatively movable coifitrolling,v valve and valve casing having formed therein ycoopeiatimg portsfor causing said valve in one position thereoil relative to said casing to connect saidisource .of supply to said end ot said cylinder, when in another relative position to interrupt the connection between said source and said end of said cylinder and to connect said end to the atmosphere, andvivhen in still. another relative position to cause said end ot said cylinder to be connected to the atmosphere by vfayoff said suction orifice and live Vpressure fluid to 'lievi through said .jet orifice.

on olf' a partial vacuum in saidV l0. An impact tool having, in combination, a cylinder, a hammer piston, a. tool for actuation by said hammer piston, an ejector having means forming a jet orifice and a suctionrorifice, a source of pressure fluid supply; means forming passages for connecting,` said source te an endet said cylinder and to said jet orifice, said end of said cylinder to said suction orifice and to the atmosphere, and said suction orifice to the atmosphere; the last named means includine' a relatively movable controlling;` valve and valve casing,r having` formed therein cooperating ports ter causing said valve in one position thereof relative to said. casing to connect said source of supply to said end of said cylinder, when in another relative position to interrupt the connection between: said source and said endV of said cyl.- indei' and to connect said end` tothe atmosphere independent-ly of said ejector, and

when in still another relative position lto cause said end of said cylinder to be con.- nected to the atmosphere by Way of said suction orifice and live pressure fluid to flow through said orifice..

l1.. An impact tool leaving;y inI combination, a cylinder, a hammer piston', a tool: ,for actuation by said hammer piston, a source of pressure fluid supply a control.- ling valve an, ejector having a jet orificeY and a, suction orifice; conduit means. connecting); said source of. supply to said valve,

and connecting said valve to .one end oty said;

cylinder, the atmosphere, and said jet and.

nection between. said source of supplyy and;

said cud ot said cylinder.

i2.. in. a. hand heldv impact tool, the coinbination with a cyiinder and a; hammer piston ot an ejector, a source of inotivefluid supply, means including a; controlling` valve and ports and passages controlled thereby for alternately admitting motive fluid; from said source leone end oi'` said cylinderand exhausting;` said end and for .creating suction in said end. by saidejector'; said valvel having one position to effect supply of mo,- tivo fluid to said ond of said cylinder to cause the pistonto make itspower stroke,`

a second position to effect interruption of Asaid supply and connection of. said end ot said cylinder to the atmospherefor eXha-ustino' the motive fluid admitted in the` first position of said valve, and a third position to eflieet interruntion of said suaol f to said.

cylinderand interruption of` that connection to the atmosphere effected` in the Secondv Y passages coiitrolled thereby for alternately admitting` motive fluid from said source to one end of said cylinder and exhausting said end. and for croatingf Suction i'n-y said end by said; ejector, saldi valve having an intermediate position. and; a: position on eachi side of. said intermediate; position, said: valve in its. intermediate position causingl said ports and; passagesto.v exhaust said end of said cylinder, iii one oi its other positions causing said ports'` and passages to; connect said` source of motive. fluid. supply to said; end

of. said cylinder for causing the piston to.

li'ialre its power.l stroke, and. iii'the remaining-of. its other positions causing'said ports and passages to; connect said.y source of motivo Huid supplyl and; said end of said cylinder tosaidi ejector for subjecting said cyl.- indei to suctionS for returning said piston.

M.' In. a `hand held impact tool, aI cylinder having' a hammer piston therein, a valve cl'iamber, said cylinder having openings at opposite endsI and being imperforate between, said.lopenings,..one of saidy openings leading to the atmosphere and the other to said: valve chamber, means. forming an ejector, a source of motive fluid: supply,l a valvein. said valve chamber,.means 'forming ports and. passages controlled by said; valvefor. effecting in one position. of saidy valve admission of motive fluid. from said4 valve chamber tosaid cylinder by Way of the` opening leading; to said chamber from said cylinder, in anotherA position of saidy valve connection; of'-V the last named. openingl tothe atmosphere,. and in a third position of said Valve connection of .said last named openingto said; ejector andf supply of motive fluid to said ejector.

In a handheld impact tool, a; cylinder.,. av hammer piston; therein, said cylinder hav.-

ing at opposite ends fluid conductingv passages for the fluid4 actuating said piston and controlled-d thereby,- said valve-being movable fory effecting by said ports. and passages ad-Y mission ot motive fluid toioneend o fzsaid cylinder for causing said piston to make itsl power stroke and tor then exhausting said end, and means including ani ejector and. ports and passages controlled by saidvalve for subjecting said end to, suction when said piston is to be returned to said end after exhausting said end. y. f-

16 A; handheld impact tool having', in: combinatioin, a cylinder, a. piston-therein, means including` ports and1 passages and a manually operated distributingfr valve for controlling the motive fluid for actuating` said piston, said valve having a neutral position in Which the flow of motive Huid is interrupted and a position at each'side ot said neutral position for causing flow oi" inotive fluid for effecting' movement of said piston in opposite directions, and means forming an expansible chamber device for moving said valve from one of the last named positions to said neutral position, said last mentioned means comprising ports and passages controlled by said valve.

17. A hand held fluid actuated hammer having, in combination, a cylinder, a hainmer piston; and means for effecting actuation of said piston in opposite directions including a motive fluid supply connection, a manually actuated valve, and motive fluid conducting ports and passages controlled by said valve; said valve at one end of its travel rendering said means operative to admit inotive fluid from said connection to said cylinder to cause the stroke of said piston in one direction, at an intermediate position rendering said means operative to exhaust the motive fluid admitted to said cylinder, and at the opposite end of its travel rendering said means operative to effect flow of motive fluid from said connection for effecting a return stroke of said piston. Y

18. A hand held fluid actuated hammer having, in combination, a cylinder, a hammer piston, a tool operated upon Vby said hammer piston, a source of motive fluid supply, a manually actuated valve and ports and passages controlled thereby, means forming an ejector; said valve at one end of its travel causing said ports and passages to supply motive fluid from said source to said cylinder for causing the power stroke of said piston, at a position intermediate the ends of its travel causing said ports and passages to exhaust said fluid admitted to said cylinder, and at the opposite end of its travel causing said ports and passages to supply said ejector-with motive fluid for effecting suction in said cylinder for causing a return of said piston.

19. A hand held fluid actuated hammer having, in combination, a cylinder, Va ham- Vmer piston in said cylinder, a manually operated controllingvalve, a source of motive i su i i s i ii s and flu ppl neai for ni g port l passages controlled by said valve-for effectingr action of said piston by motive fluid` from said source, said valve at one end of its travel causing` said ports and passages to admit motive fluid from said source to said cylinder to edect the power stroke-of said hammer piston; means including cooperating opposed pressure surfaces and conduit means controlled by said valve for causing fluid pressure to build up between said pressure surfaces when said valve is at said end of its travel for urging movement of said' valve from said end to a position intermediate the ends of its travel, said valve when in such intermediate position exhausting from said cylinder the fluid causing said power stroke of the piston and exhausting the fluid from between said pressure surfaces.` Y

20. A hand held fluid actuated hammer having, in combination, a cylinder', a hammer piston in said cylinder, a source of inotive fluid supply, a manually controlled valve and ports and passages controlled thereby for effeeting'actuationof said piston, manually actuated means for moving said valve, said VVvalve having a position to effect by said ports and passages exhaust of the rearward end of said cylinder and'havy Aing an end position to effect supply of said rearward end with motive fluid from said source, means including opposed pressure surfaces .and ports and passages controlled by manual movement of said valve for creating when said valve is in said end position a force urging movement of said valve yfrom said end position toits first named po- Acylinder with motive fluid for driving said hammer forward andY for causing said mo-Y L tive fluid to act against said pressure surface ofsaid valve for urging said valve toward its intermediate position, said valve when moved to its intermediate position exhaust-V ing the rearward end of said cylinder and the motive fluid acting against said pressure surface, said valve when moved to its other lli) liso

end position supplying motivefluid to said i ejector and"connectingl the suction orifice of said ejector to thel rearward end of said cylinder. j l

ln testimony whereof, l have. name to this specification.

Eniviis'r i-i. siiiirr,

signed my lllfi, 

